The application and use of fiber optic cable in communications systems is standard practice with many major telephone companies. The advantages of usages in communication are well known.
More recently, electric utilities have developed an interest in cables which include a central core optic cable surrounded by standard electrical cable strands. Some of the major utilities have made such installations.
The cable configuration, including the central core optic cable, is similar to that disclosed by Dey et al in U.S. Pat. No. 4,491,387. In that configuration, Dey indicates a seamed tube as the housing for the optic cable. Cables presently in domestic use provide a seamless aluminum tube for this purpose. This cable structure, in essence, has a standard electrical cable functioning as a carrier for the fiber optic cable. There are two reasons why this conductor is being adopted by electric utilities. One is that they can use the fiber optic cable to monitor and control the performance of electrical equipment along electric lines. For example, the ampacity of power transformers at substations can be continuously monitored. Where ampacities exceed the maximum rating of the transformer, they can, through the use of a electronic and/or electrical control equipment, disconnect the transformers, thus preventing overloading and possible field failure.
A further reason for the use of such cables is that it allows the electric utilities to lease the excess fiber optic cable capacity to interested telephone companies.
Electrical connectors are now available for splicing and dead-ending such composite cable, including specially designed equipment to splice and terminate the fiber optic cable.
Making standard tap connections for grounding the electrical strands of this type of cable has posed a problem. Clamping pressure must be limited to prevent damage to the fiber optic cable. Conventional clamps now in common use for grounding do not limit the pressure applied to the conductors. Bolting torques now recommended for these clamps could collapse the aluminum tube which houses and protects the fiber optic cable.
Accordingly, one of the major objects of the present invention is to provide a conductor for grounding a cable which applies a predetermined constant pressure to the cable to avoid damage to the fiber optic cable while providing the necessary clamping pressure for good mechanical and electrical performance under fault conditions.
A further object is to provide a connector for grounding of cables which prevents damage to such cables having a central core optic cable.
A still further object is to provide a connector which is designed to accommodate a range of conductor diameters.
These, and other, objects of the invention will become apparent from the following description and associated drawings.